All three projects proposed in the program project grant application will utilize the mouse behavioral core facilities including motor and cognitive testing. Motor testing is most often done as a counterpart to histopathology to assess brain damage after stroke, as well as effects of molecular pathway manipulation and putative therapeutic strategies. More recently it has become appreciated that stroke also induces cognitive deficits as well, yet cognitive testing is only occasionally used as a measure of functional outcome after experimental stroke. In contrast, cognitive output is a mainstay of assessment in traumatic brain injury (TBI) models. Most cognitive testing reported involves use of memory acquisition tests such as the Morris water maze, T-maze, novel object recognition, and others. Because each of the individual projects relies on behavioral testing as important experimental outputs, the sensitivity, validity, and reliability of behavioral testing is a central issue in the PPG overall. This is especially true when comparing and interpreting behavioral data across diverse injury models such as stroke and TBI. The goal of the behavioral core is to provide a central facility to each PI that will (1) assist in experimental design and selection of appropriate testing methodology to answer specific questions in individual brain injury models, (2) ensure a uniform non- varying testing environment to provide stable environmental and test conditions longitudinally across experiments, and (3) provide hands on assistance and technical training in motor and cognitive testing for technicians, postdoctoral fellows, graduate students, faculty and others interested in expanding the behavioral testing repertoire of their labs. The behavioral core will be equipped to perform motor (corner test, cylinder test, grid walk, and tape removal) and cognitive (Morris water maze. Y-maze, novel object recognition, and radial arm maze) testing using video camera recorders and Any Maze software. In addition to its availability for all of the Pis, the behaviroal core facility will be open for use by other NIH-funded investigators at MGH as time and space allow. RELEVANCE (See instructions): The purpose of the PPG is to utilize and assess long term regenerative strategies to promote recovery after stroke and traumatic brain injury. Functional (motor and cognitive) outcome measures require robust testing methods that are consistent over time to ensure their reliability and validity. The Behavioral Core will provide equipment and standardized protocols to ensure validity of data across experiments.